Cron Cost Guard

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name: cron-cost-guard description: Audit AI agent cron jobs for token cost risks, model-switch loops, and session isolation failures. Use when setting up new cron jobs, debugging unexpected token usage spikes, auditing multi-agent cron configurations, or after a cost anomaly. Triggers on "audit crons", "check cron costs", "token budget", "cron safety", "cost spike", "model switch error", "session isolation", "cron health check".

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Cron Cost Guard

Prevent silent token budget burns from misconfigured AI agent cron jobs.

Quick Audit

Run this checklist on every cron setup or when investigating a cost spike:

1. Session Isolation (Critical)

Check every cron job for session binding conflicts:

cron list (includeDisabled: true)

Red flags:

sessionKey: "agent:main:main" with sessionTarget: "isolated" → stale binding, will cause model conflicts

agentId pointing to a different agent than the session owner → cross-agent model contamination

consecutiveErrors >= 3 → likely stuck in a retry loop

lastError containing LiveSessionModelSwitchError → model-switch loop confirmed

Fix: Remove and recreate the job without sessionKey. Set sessionTarget: "isolated".

2. Model Conflicts

In multi-agent setups (e.g., Agent A on Claude, Agent B on GPT), each agent's crons must be scoped to that agent only.

Set agentId explicitly on every cron job

Set model explicitly in the payload when available

Never let Agent B's cron inherit Agent A's session model

3. System Prompt Size

Audit injected workspace files:

wc -c MEMORY.md SOUL.md AGENTS.md TOOLS.md USER.md QUEUE.md

Target: < 20KB total injected. Move large files (playbooks, heartbeat templates, reference docs) to references/ for on-demand reading.

| Size | Status | |------|--------| | < 20KB | Healthy | | 20-40KB | Trim soon | | > 40KB | Trim now — every API call is bloated |

4. Cost Monitoring

sessions_list (limit: 10, messageLimit: 1)

Look for sessions with high estimatedCostUsd but low output tokens — that's a retry loop signature.

| Metric | Healthy | Warning | Critical | |--------|---------|---------|----------| | Cron consecutive errors | 0 | 1-2 | ≥3 | | Session cost (cron) | < $0.50 | $0.50-2.00 | > $2.00 | | Model switch retries | 0 | 1-2 | ≥3 |

Diagnosis: Token Spike

For detailed diagnosis steps and post-incident checklist, read references/diagnosis.md.

Prevention Rules

1. Every cron job: sessionTarget: "isolated", no stale sessionKey 2. Every cron job: explicit timeoutSeconds (never unlimited) 3. Multi-agent: explicit agentId matching the agent that should run it 4. After changing default model: audit all cron jobs for conflicts 5. Weekly: check consecutiveErrors across all jobs — anything ≥ 3 needs investigation